Hi, 

Method gaiaGetVectorLayersList returns wrong fields names.

If I use spatialite binary, I've got the correct fields names (id_compt, type_compt):
spatialite> .schema compteur_routier
CREATE TABLE compteur_routier (
id INTEGER PRIMARY KEY,
geom POINT,
id_compt TEXT,
type_compt TEXT,
angle INTEGER,
id_tmp INTEGER
);

But If I use gaiaGetVectorLayersList method (thanks to demo5 example), I get wrong field name (id_compteur and type_compteur):
./demo5 -d ~/work/tmp/test_files/test_spl.sqlite -t compteur_routier       
SQLite version: 3.25.3
SpatiaLite version: 5.0.0-beta1



****** VectorLayersList (mode=OPTIMISTIC) *********
VectorLayer: Type=BasedOnSqlTable TableName=compteur_routier
	GeometryName=geom SRID=2154 GeometryType=POINT Dims=XY
	RowCount=7
	ExtentMin 848046.525865 / 6425228.263184
	ExtentMax 852051.441057 / 6429544.178129
	ReadOnly=FALSE Hidden=FALSE
		Field #0) FieldName=id
			IntegerValues=7 
			IntRange 1 / 7
		Field #1) FieldName=id_compteur
			TextValues=7 
			MaxSize/Length=4
		Field #2) FieldName=type_compteur
			TextValues=7 
			MaxSize/Length=9
		Field #3) FieldName=angle
			IntegerValues=7 
			IntRange 15 / 180
		Field #4) FieldName=id_tmp
			IntegerValues=7 
			IntRange 1 / 7
		Field #5) FieldName=geom
			BlobValues=7 
			MaxSize/Length=60



sample successfully terminated

You can download test files here : https://issues.qgis.org/attachments/download/13111/test_files.zip

At first, it was a reported bug in QGIS (https://issues.qgis.org/issues/19598) : the problem seems to come from the fact that the user rename the table, create a new one with new fields name, then populate new one with the old one data.

QGIS reads field name thanks to gaiaGetVectorLayersList method.

Regards,
Julien

demo5 does not run correctly in its present form:<br>

./demo5 -d test_spl.sqlite -t compteur_routier
-I-> main argc[5] argv[0][/home/mj10777/000_links/libspatialite_fossil/libspatialite.dustbin/examples/.libs/lt-demo5]

<hr>
To following prevents the demo from running:<br>
<pre>
    if (argc > 1 || argv[0] == NULL)
	argc = 1;		/* silencing stupid compiler warnings */
</pre>
<hr>
After enclosing inside a '#ifdef 0', the demo runs correctly without warnings during compilation.<br>
<pre>
-I-> main argc[5] 
-I-> main argv i[1] value[-d]
-I-> main argv i[2] value[test_spl.sqlite]
-I-> main argv i[3] value[-t]
-I-> main argv i[4] value[compteur_routier]
</pre>
<hr>
results reported by user are returned<br>
<pre>
Field #1) FieldName=id_compteur
          TextValues=7 
	  MaxSize/Length=4
Field #2) FieldName=type_compteur
	  TextValues=7 
	  MaxSize/Length=9

</pre>

The TEXT columns have an extra '<b>eur</b>' added<br>

<pre>
0	id	INTEGER
1	geom	POINT
2	id_compt	TEXT
3	type_compt	TEXT
4	angle	INTEGER
5	id_tmp	INTEGER
</pre>

gaiaGetVectorLayersList calls gaiaGetVectorLayersList_v4<br>
There a SELECT is done against <b>vector_layers_field_infos</b><br>

returning:<br>
<pre>
0	id
1	id_compteur
2	type_compteur
3	angle
4	id_tmp
5	geom
</pre>
<hr>
Cause of problem:<br>
User has changed a TABLE that is administered by spatialite (containing a geometry-column) using a <b>sqlite3</b> command (ALTER TABLE compteur_routier RENAME TO compteur_routier_sav;)<br>
<hr>
<b>sqlite3</b> does not know, nor care's, about administration TABLEs of any extension.<br>
Therefore <b>vector_layers_field_infos</b> was not adapted with the new column names<br>
(in this case the entries of the administration should have been <b>removed</b> before the new TABLE, with the same name, was created)<br>
<hr>

For this scenario, the following should be done, using the present fossil version, with <b>sqlite3</b> version >= 3.25<br>
<ul>
 <li><b>RenameTable</b> (administration TABLEs will be adapted)</li>
 <li>create and fill new table from old table</li>
 <li><b>DropTable</b> old table (administration TABLEs will be adapted)</li>
</ul><br>
another combination would have been:
<ul>
 <li><b>CloneTable</b> create a copy of the TABLE with data</li>
 <li><b>DropGeoTable/DropTable</b> old table (administration TABLEs will be adapted)</li>
</ul>
 <li>create and fill new table from cloned table</li>
 <li><b>DropGeoTable/DropTable</b> cloned table (administration TABLEs will be adapted)</li>
</ul><br>
DropGeoTable has been Deprecated, use DropTable instead.